|Name of Activity
||gear, gear ratios, build, machine, tug-o-war, competition, prototype, Engineering Design Process, torque
||4, 5, 6, 7, 8, 9+
||3 Hours Total
||Students will use their knowledge about gears and gear ratios to build a machine that will play tug-o-war against another classmate’s.
||To apply building techniques and knowledge about gears to an activity challenge.
RCX or NXT LEGO kits
Assortment of extra LEGO pieces, especially gears and beams
Engineer’s Planning Sheet
|Preparation and Set Up:
Collect necessary materials
Arrange students into groups of 2
Decide how you will distribute extra pieces
Write design requirements on the board
||Review gears, gear ratios, and torque.
Engineering Design Process
- Tell students that in this challenge they will be playing tug-o-war by building a machine that can provide enough torque to pull on another machine doing the same thing. String will be tied between the two, and a machine will have to pull the other over a line of tape in order to win.
- Make sure to review how gears work, gear ratios, and using gears for torque vs. speed. Also explain the engineering design process.
- Tell students the requirements for their tug-o-war contenders. Examples of requirements are:
- Must use gears
- Must have a sensor
- Allow the class to brainstorm different ideas for their machines. Have them plan out and draw their design on the engineering planning sheet.
- Distribute materials and have students start building. You may have to assist students with tying string to their machine.
- After the students finish building, pair up machines and tie them to either end of a string, making sure the middle of the string is right above the tape on the ground, and that both machines are equidistant from the tape.
- Have the students start their machines. Whoever’s machine gets pulled over the line first, loses.
- After the students finish, review the activity with the class. Have them share their ideas, ask groups to explain what the hardest part of the challenge was, etc.
||Have students add more gears
Make a classwide tug-o-war competition. Whose is the “strongest”?
Allow those who lose to redesign and compete against each other again